A Review of Geoconservation Values
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Geoconservation Values of the TWWHA and Adjacent Areas 3.0 GEOCONSERVATION AND GEOHERITAGE VALUES OF THE TWWHA AND ADJACENT AREAS 3.1 Introduction This section provides an assessment of the geoconservation (geoheritage) values of the TWWHA, with particular emphasis on the identification of geoconservation values of World Heritage significance. This assessment is based on: • a review (Section 2.3.2) of the geoconservation values cited in the 1989 TWWHA nomination (DASETT 1989); • a review of relevant new scientific data that has become available since 1989 (Section 2.4); and: • the use of contemporary procedures for rigorous justification of geoconservation significance (see Section 2.2) in terms of the updated World Heritage Criteria (UNESCO 1999; see this report Section 2.3.3). In general, this review indicates that the major geoconservation World Heritage values of the TWWHA identified in 1989 are robust and remain valid. However, only a handful of individual sites or features in the TWWHA are considered to have World Heritage value in their own right, as physical features considered in isolation (eg, Exit Cave). In general it is the diversity, extent and inter-relationships between numerous features, sites, areas or processes that gives World Heritage significance to certain geoheritage “themes” in the TWWHA (eg, the "Ongoing Natural Geomorphic and Soil Process Systems" and “Late Cainozoic "Ice Ages" and Climate Change Record” themes). This "wholistic" principle under-pinned the 1989 TWWHA nomination (DASETT 1989, p. 27; see this report Section 2.3.2), and is strongly supported by the present review (see discussion and justification of this principle in Section 2.2). A corollary of this principle is that many of the particular features and sites contributing to a theme of World Heritage significance may not individually be of World Heritage significance, but rather may individually be considered to have lower levels of significance (i.e., significance at local to national levels). Geoconservation inventory work since 1989 (see Section 2.4) has indeed resulted in the identification of a large number of features contributing to World Heritage themes in the TWWHA, most of which have individually been assigned lower significance levels; these features and their significance levels have been recorded in the Tasmanian Geoconservation Database (TGD 2001). This section (3.0) focuses primarily on the geoconservation themes and sites of World Heritage significance in the TWWHA; however, Appendix (1.0) provides a comprehensive listing of all features and sites – of all significance levels - within the TWWHA that have been listed on the TGD, together with the significance levels assigned to each. Whereas many of these features contribute to the World Heritage themes discussed in this section, there are also numerous sites listed which both are of less than World Heritage significance individually, and which also do not contribute to World Heritage themes. Such features are still of conservation significance, and warrant appropriate protective management, however they are not the primary focus of this review. A comprehensive statement of the geoconservation values recognised in the TWWHA at the present time – at all levels from World Heritage to Local significance levels - can be considered to be comprised by the World Heritage themes and features identified in this Section (3.0), the individual features contributing to those themes including those listed in Appendix (1.0), together with all those other features of lesser significance levels listed in Appendix (1.0). Some of the geodiversity phenomena previously cited in the 1989 TWWHA nomination as contributing to World Heritage values do not withstand scrutiny as having World Heritage 65 Geoheritage Values – Tasmanian Wilderness World Heritage Area significance (eg, Precambrian multiple fold phases, Collingwood River eclogites). In general this is because these sites cannot be ascribed World Heritage value as individual features, and also do not significantly contribute to a broader identifiable World Heritage theme. Most of these features are considered to have geoheritage significance at State or even National levels, but not at World levels, and so are best considered as non-World Heritage geoconservation values which nonetheless contribute to the geoheritage value of the TWWHA and remain worthy of conservation management (as noted above). A significant result of this review is that, whilst numerous features contributing to the significance of World Heritage themes have been newly identified or better understood, and significant new aspects of previously identified themes have been discovered (e.g., significance of palaeokarst in cave development processes, influence of blanket bogs on fluvial landforms, etc), no entirely new World Heritage geoconservation themes, beyond those previously identified in the 1989 nomination, have been identified. It is likely that this is at least partly because most scientific research conducted in the TWWHA since the 1989 nomination has been funded and directed towards facilitating better management of those World Heritage value themes for which the TWWHA was inscribed in the World Heritage List. 3.2 TWWHA World Heritage Geoconservation Values This section presents the World Heritage geoconservation values of the TWWHA, as recognised as an outcome of this review, in two different formats. Section (3.2.1) below summarises the values in tabular form, and provides a direct comparison between the values recognised in the 1989 TWWHA nomination, and those values recognised in the current (2002-03) review. Section (3.2.2) following organises the recognised values according to themes, and provides the justification for the recognised values based on the current World Heritage criteria (Section 2.3.3) and on current geoconservation significance assessment procedures (Section 2.2). 3.2.1 Table of TWWHA World Heritage Geoconservation Values (by World Heritage Criteria) Organised according to current (1999) World Heritage criteria. Values recognised in 1989 TWWHA Reviewed / additional / expanded values nomination (2002-2003) Criterion (i) Be outstanding examples representing major stages of earth’s history, including the record of life, significant on-going geological processes in the development of land forms, or significant geomorphic or physiographic features. The wilderness character of the TWWHA Ongoing Natural Processes theme: means that it is one of only 3 large temperate regions in the southern hemisphere where This review strongly supports the outstanding natural processes (including on-going universal value of the large area of the geomorphic and soil processes, which are TWWHA in which effectively natural included within the category of "on-going geomorphic and soil processes continue as an geological processes" under Criterion i) overarching Ongoing Natural Processes theme continue to operate in an unmodified fashion, of World Heritage significance. thus it provides a global "benchmark" for temperate natural processes (DASETT 1989, p. 27). This over-arching World Heritage theme has been classified into several sub-themes, as The following ongoing geomorphic and soil detailed below, several of which not only 66 Geoconservation Values of the TWWHA and Adjacent Areas processes were cited in the 1989 TWWHA contribute to the overall value of this theme, but nomination as globally significant because they also have World Heritage significance in their are ongoing in an essentially undisturbed own right. environment, and hence have world value as "benchmark" processes against which to compare the effects of human activity elsewhere: Fluvial processes are ongoing in an essentially Ongoing Fluvial Geomorphic Process Systems undisturbed environment (very briefly sub-theme: mentioned only). Systematic research into TWWHA fluvial systems has been in progress only since the late 1980's. Effectively undisturbed natural fluvial process systems of the TWWHA comprise the largest area of undisturbed temperate fluvial glacial-influenced systems free of contemporary glacial (glacio-fluvial) influences in the southern Hemisphere and probably the world. As such, the Ongoing Fluvial Geomorphic Process Systems sub-theme has outstanding universal value in its own right, and also as a major element of the Ongoing Natural Processes World Heritage theme. Several individual fluvial geomorphic systems of the TWWHA have outstanding universal value in their own right: • The New-Salisbury River Basin has outstanding universal value in its own right as the largest entire source-to-sea fluvial system in the TWWHA (and Tasmania as a whole) that is free of effective Aboriginal or European process disturbances, and includes a wide diversity of undisturbed fluvial (and karst) sub-systems. • The Birches Inlet – Sorell River – Pocacker River Tectonically-Influenced Peat Land Fluvial System (and related marine terraces at Birches Inlet) has outstanding universal value in its own right as an ongoing fluvial process system exemplifying tectonic and peat soil influences on fluvial processes. The largest fluvial system in the TWWHA, the Gordon River basin, is unfortunately partly disturbed, and its World Heritage value under this theme is under threat. However, major tributary catchments of the Gordon System remain largely or wholly undisturbed. 67 Geoheritage Values – Tasmanian Wilderness World Heritage Area Lakes were noted in the 1989 TWWHA Ongoing Lacustrine Process Systems sub- nomination